Method for producing friction plate and apparatus therefor

ABSTRACT

There is provided a method for producing a friction plate, capable of improving the throughput of friction material and reducing the time and work required for adhering friction material segments to a core plate. The method produces a friction plate having oil grooves communicating between the internal periphery and the external periphery, by fixing friction material segments formed from a friction material to a core plate, and is featured by forming the oil grooves by plastic working of the friction material and fixation of the friction material segments with predetermined gaps therebetween to the core plate.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a division of application Ser. No. 09/296,294 filedApr. 22, 1999.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for producing a friction plateadapted for use in an automatic transmission or a lock-up clutch ofvehicles such as automobiles and an apparatus therefor.

2. Related Background Art

In the prior art, plural segments of friction material are adhered to acore plate with a predetermined gap between the segments, therebyforming oil grooves for lubricating oil on the friction plate.

FIG. 8 shows an example of such conventional method for producing afriction plate. Segments of the friction material are prepared forexample by punching from a tape 5 of the friction material. The segments3 of the friction material are fixed on a core plate 1 with gaps 4 inthe circumferential direction to form a friction plate 10, and such gaps4 constitute oil grooves.

The above-described conventional method for forming the friction platehas been associated with the following drawbacks:

1) As the plural segments of the friction material are extracted fromthe friction material tape and are adhered with predetermined gaps tothe core plate, there are required time and work for forming the oilgrooves of the required number; and

2) Also as it is necessary to obtain the friction material segments of arelatively large number from the tape, the throughput of the materialsuch as the tape of the friction material is undesirably low, resultingin a significant waste of the material.

SUMMARY OF THE INVENTION

In consideration of the foregoing, an object of the present invention isto provide a method for producing the friction plate capable ofimproving the throughput of the friction material and reducing the timerequired for adhering the segments of the friction material to the coreplate.

For attaining the above-mentioned object, the present invention isfirstly featured by a method for producing a friction plate formed byfixing friction material segments, formed from a friction material, to acore plate and having oil grooves communicating between the internalperiphery and the external periphery of the segments:

wherein the oil grooves are formed by plastic working of the frictionmaterial and fixation of the friction material segments with apredetermined gap therebetween to the core plate.

Also the present invention is secondly featured by a method forproducing a friction plate formed by fixing friction material segments,formed from a friction material, to a core plate and having oil groovescommunicating between the internal periphery and the external peripheryof the segments:

wherein the oil grooves are formed by cutting of the friction materialand fixation of the friction material segments with a predetermined gaptherebetween to the core plate.

Also the present invention is thirdly featured by an apparatus forproducing a friction plate formed by fixing friction material segments,formed from a friction material, to a core plate and having oil groovescommunicating between the internal periphery and the external peripheryof the segments, comprising:

means for punching a band-shaped friction material to obtain pluralfriction material segments;

means for holding the friction material segments by stacking on a metalmold or a jig and pushing out the friction material segments insuccession to a side opposite to the metal mold; and

means for pressing and adhering the friction material segments to thecore plate;

wherein the oil grooves are formed by plastic working of the frictionmaterial and fixation of the friction material segments with apredetermined gap therebetween to the core plate.

Also the present invention is fourthly featured by an apparatus forproducing a friction plate formed by fixing friction material segments,formed from a friction material, to a core plate and having oil groovescommunicating between the internal periphery and the external peripheryof the segments, comprising:

means for punching a band-shaped friction material to obtain pluralfriction material segments;

means for holding the friction material segments by stacking on a metalmold or a jig and pushing out the friction material segments insuccession to a side opposite to the metal mold; and

means for pressing and adhering the friction material segments to thecore plate;

wherein the oil grooves are formed by cutting of the friction materialand fixation of the friction material segments with a predetermined gaptherebetween to the core plate.

Also the present invention is fifthly featured by a friction plateformed by fixing friction material segments, formed from a frictionmaterial, to a core plate and having oil grooves communicating betweenthe internal periphery and the external periphery of the segments:

wherein the oil grooves are formed by plastic working of the frictionmaterial and fixation of the friction material segments with apredetermined gap therebetween to the core plate.

Also the present invention is sixthly featured by a friction plateformed by fixing friction material segments, formed from a frictionmaterial, to a core plate and having oil grooves communicating betweenthe internal periphery and the external periphery of the segments:

wherein the oil grooves are formed by cutting of the friction materialand fixation of the friction material segments with a predetermined gaptherebetween to the core plate.

Also the present invention is seventhly featured by a friction plateformed by fixing friction material segments, formed from a frictionmaterial, to a core plate and having oil grooves communicating betweenthe internal periphery and the external periphery of the segments:

wherein the friction material segments are fixed with a predeterminedgap therebetween to the core plate and then subjected to cutting forforming the oil grooves.

The time required for adhering work can be reduced since the frictionmaterial segments of a number fewer than in the prior art are adhered tothe core plate. Also the throughput of the material can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a first embodiment of the present invention and is a planview of the friction plate, showing the mode of adhesion of the frictionmaterial segments to the core plate;

FIG. 2 shows a second embodiment of the present invention and is a planview of the friction plate, showing the mode of adhesion of the frictionmaterial segments to the core plate;

FIG. 3 shows a third embodiment of the present invention and is a planview of the friction plate, showing the mode of adhesion of the frictionmaterial segments to the core plate;

FIG. 4 is a plan view of the friction plate produced by the thirdembodiment;

FIG. 5 is an elevation view of the friction material segments showing anexample of the groove formed therein;

FIG. 6 is an elevation view of the friction material segments showinganother example of the groove formed therein;

FIG. 7 is a view showing an apparatus for producing the friction plateof the respective embodiments; and

FIG. 8 is a plan view of the friction plate, showing a conventionalmethod for producing the same.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now the present invention will be explained in detail by preferredembodiments thereof, with reference to the attached drawings, whereincorresponding components are represented by corresponding numbers.

FIG. 1 shows a first embodiment of the present invention and is a planview showing the mode of punching plural friction material segments froma tape of the friction material and adhering the segments to an annularcore plate. The band-shaped friction material, or the friction materialtape 16, has predetermined thickness and width. Plural friction materialsegments 11 of a same shape are obtained for example by press punchingof the friction material tape 16.

The friction material segment 11 has an arc shape, having apredetermined radial width and a predetermined circumferential width.The friction material segment 11 is composed of an external peripheryportion 11 a of a curvature same as that of the annular core plate 12,an internal periphery portion 11 b, and circumferential edge portions 11c for connecting the external periphery portion 11 a and the internalperiphery portion 11 b at both ends thereof in the circumferentialdirection.

The friction material segments 11 are adhered and fixed, for examplewith an adhesive material, to both top and rear faces of the core plate12 or a face thereof. In the first embodiment shown in FIG. 1, fourfriction material segments 11 are fixed circumferentially to the coreplate 12. At the adhesion, a predetermined gap is formed between theedges 11 c of the friction material segments 11 to form oil grooves 14for the lubricating oil in the automatic transmission.

As the width of the friction material segments 11 in the radialdirection thereof is smaller than that of the core plate 11 in theradial direction thereof, a substantially annular groove 15 is formed onthe core plate 12 after the adhesion of the friction material segments11. This annular groove 15 communicates with the oil grooves 14. In casethe friction material segments 11 are adhered on both faces of the coreplate 12, respective grooves 15 are naturally formed on both facesthereof. As shown in FIG. 1, the friction material tape 16 is providedin advance with a groove 13 by plastic working such as pressing orroller pressing or by cutting. Consequently, the groove 13 is formed inthe friction material segment 11 at the preparation thereof for exampleby punching from the friction material tape 16. The groove 13 isprovided at the approximate center of the friction material segment 11,penetrating through the segment in the radial direction. Consequently,after the adhesion of the friction material segments 11 on the coreplate 12, the oil grooves 14 and the second oil grooves 13 arepositioned radially, with a substantially constant pitch. The grooves 13also communicate with the annular groove 15, thus communicating alsowith the oil grooves 14.

In the present embodiment, four friction material segments 11 areadhered to the core plate 12, but such number is not limited to four andmay be selected otherwise. Also the groove 13 provided in the frictionmaterial tape 16 need not be limited to one but can also be provided inplural units.

The friction plate 20 formed by fixing the friction material segments 11to the core plate 12 is lubricated with lubricating oil in the actualuse, and the presence of the groove 15 communicating with the oilgrooves 14 and the grooves 13 achieves smooth flow of the lubricatingoil, thereby improving the lubricating ability. In particular, there isensured smooth flow of the lubricating oil in the radial direction fromthe external periphery side to the internal periphery side of thefriction plate 20 and in the opposite direction from the internalperiphery side to the external periphery side.

FIG. 2 shows a second embodiment of the present invention and is a planview showing the mode of punching plural friction material segments fromthe friction material tape and adhering the segments to the core plate.As the basic configuration is similar to that in the first embodiment,there will be explained the different points only.

The friction material segments 11 are adhered and fixed, for examplewith an adhesive material, to both top and rear faces of the core plate12 or a face thereof. In the second embodiment, a groove 17 in thefriction material segment 11 is not provided in advance on the frictionmaterial tape 16 but is formed by plastic working such as pressing atthe punching of the friction material segment 11 from the frictionmaterial tape 16.

Consequently, after the adhesion of the friction material segments 11 onthe core plate 12, the oil grooves 14 and the second oil grooves 17 arepositioned radially, at a substantially constant pitch. The grooves 17also communicate with the annular groove 15, thus communicating alsowith the oil grooves 14.

In the present embodiment, four friction material segments 11 areadhered to the core plate 12, but such number is not limited to four andmay be selected otherwise. Also the groove 17 formed simultaneously withthe punching need not be limited to one but can also be formed in pluralunits.

The friction plate 60 formed by fixing the friction material segments 11to the core plate 12 is lubricated with lubricating oil in the actualuse, and the presence of the groove 15 communicating with the oilgrooves 14 and the grooves 17 achieves smooth flow of the lubricatingoil, thereby improving the lubricating ability. In particular, there isensured smooth flow of the lubricating oil in the radial direction fromthe external periphery side to the internal periphery side of thefriction plate 60 and in the opposite direction from the internalperiphery side to the external periphery side.

FIGS. 3 and 4 show a third embodiment of the present invention. FIG. 3is a plan view showing the mode of punching plural friction materialsegments from the friction material tape and adhering the segments tothe core plate. FIG. 4 is a plan view of the completed friction plate70. As the basic configuration is similar to that in the firstembodiment, there will be explained the different points only.

The friction material segments 11 are adhered and fixed, for examplewith an adhesive material, to both top and rear faces of the core plate12 or a face thereof. In the third embodiment, a groove 18 in thefriction material segment 11 is not provided in advance on the frictionmaterial tape 16 nor formed at the punching of the friction materialsegment 11 for example by pressing from the friction material tape 16,but is formed by pressing, roller pressing or cutting after the frictionmaterial segment 11 is adhered to the core plate 12, namely at the finaladhesion.

Consequently, after the adhesion of the friction material segments 11 onthe core plate 12, the oil grooves 14 and the second oil grooves 18 arepositioned radially, at a substantially constant pitch. The grooves 18also communicate with the annular groove 15, thus communicating alsowith the oil grooves 14.

In the present embodiment, four friction material segments 11 areadhered to the core plate 12, but such number is not limited to four andmay be selected otherwise. Also the groove 18 formed at the finaladhesion need not be limited to one but can also be formed in pluralunits.

The friction plate 70 formed by fixing the friction material segments 11to the core plate 12 is lubricated with lubricating oil in the actualuse, and the presence of the groove 15 communicating with the oilgrooves 14 and the grooves 18 achieves smooth flow of the lubricatingoil, thereby improving the lubricating ability. In particular, there isensured smooth flow of the lubricating oil in the radial direction fromthe external periphery side to the internal periphery side of thefriction plate 70 and in the opposite direction from the internalperiphery side to the external periphery side.

FIGS. 5 and 6 are elevation views of the friction material segment,showing examples of the arrangement of grooves in case of forming pluralgrooves on the friction material segment 11 for example by pressing. InFIG. 5, grooves 19 are formed on the friction material segment 11 inradial manner with a constant pitch in the circumferential direction. Onthe other hand, in FIG. 6, grooves 29 are formed in parallel manner.This configuration, allowing formation of plural grooves in a step, issuitable for example for roller pressing or cutting.

In FIGS. 5 and 6, three grooves are formed in a friction materialsegment 11, but another number may naturally be selected.

FIG. 7 is a schematic view showing the entire configuration of anapparatus 30 for executing the methods for producing the friction plateof the foregoing embodiments. The core plate 12 is supplied from a coreplate entry unit 31 of a transporting (transfer) line 53, and thesupplied core plate 12 is transported in a direction X.

The core plate 12 is then subjected to the coating of the adhesivematerial on the lower face, by a first adhesive coating device 34 in afirst coating unit 33 for coating the adhesive. The core plate, with theadhesive material coated on the lower face, is subjected, in a frictionmaterial adhesion unit 35, to the adhesion, on the lower face, of thefriction material segments supplied from a first friction materialsupply device 44 through a lower face adhesion station 36.

Subsequently, the core plate 12 is subjected to the coating of theadhesive material on the upper face, by a second adhesive coating device38 in a second coating unit 37 for coating the adhesive. The core plate12, with the adhesive material coated on the upper face, is subjected,in a friction material adhesion unit 39, to the adhesion, on the upperface, of the friction material segments supplied from a second frictionmaterial supply device 45 through an upper face adhesion station 40.There are also shown friction material tapes 50 supplied from thefriction material supply devices 44, 45.

The core plate 12, bearing the adhered friction material segments on theupper and lower faces, is transported to a discharge unit 41, thentransported to an entry unit 42 for a post process, and is subjected tothe simultaneous application of heat and pressure for 15 to 30 secondsfor achieving final adhesion in a post process (final adhesion) unit 43to provide the completed friction plate 55.

In FIG. 7, the groove 13 of the first embodiment is formed in a step A,while the groove 17 of the second embodiment is formed in a step B, andthe groove 18 of the third embodiment is formed in a step D. In a stepC, the groove is formed on the friction material segment after theadhesion thereof but prior to the final adhesion, or after the finaladhesion.

As explained in the foregoing, the present invention provides theadvantages of:

improving the throughput of the friction material; and

reducing the time and process for fixing the friction material segmentsto the core plate.

What is claimed is:
 1. A friction plate formed by fixing frictionmaterial segments formed from a friction material to a core plate andhaving oil grooves communicating between the internal periphery and theexternal periphery, wherein: said oil grooves include a first pluralityof grooves formed by plastic working of said friction material, and asecond plurality of grooves having bottoms defined by a surface of saidcore plate, said second plurality of grooves being formed by fixing saidfriction material segments with predetermined gaps therebetween to saidcore plate.
 2. A friction plate according to claim 1, wherein said firstplurality of oil grooves include grooves formed by pressing the materialof said friction material segments.
 3. A friction plate according toclaim 1, wherein at least said second plurality of oil grooves areradial grooves.
 4. A friction plate formed by fixing friction materialsegments formed from a friction material to a core plate and having oilgrooves communicating between the internal periphery and the externalperiphery, wherein: said oil grooves include a first plurality ofgrooves formed by cutting said friction material, and a second pluralityof grooves having bottoms defined by a surface of said core plate, saidsecond plurality of grooves being formed by fixing said frictionmaterial segments with predetermined gaps therebetween to said coreplate.
 5. A friction plate according to claim 4, wherein at least saidsecond plurality of oil grooves are radial grooves.